Disclaimer: I'm a cofounder at Intigi. With https://intigi.com https://intigi.com, we've done just this, intake content from both social (Twitter) and RSS feed

Disclaimer: I'm a cofounder at Intigi. With https://intigi.com https://intigi.com, we've done just this, intake content from both social (Twitter) and RSS feeds. With Twitter, we index the full text of any linked article and make the text fully searchable. The full text provides much more data for us to search and also is a great way of deduplicating content (i.e., Tweets linking to the same article).